eaglercraft-1.8/sources/main/java/com/google/common/collect/EmptyImmutableSet.java
2022-12-25 01:12:28 -08:00

108 lines
2.1 KiB
Java

/*
* Copyright (C) 2007 The Guava Authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.common.collect;
import java.util.Collection;
import java.util.Set;
import javax.annotation.Nullable;
import com.google.common.annotations.GwtCompatible;
/**
* An empty immutable set.
*
* @author Kevin Bourrillion
*/
@GwtCompatible(serializable = true, emulated = true)
final class EmptyImmutableSet extends ImmutableSet<Object> {
static final EmptyImmutableSet INSTANCE = new EmptyImmutableSet();
private EmptyImmutableSet() {
}
@Override
public int size() {
return 0;
}
@Override
public boolean isEmpty() {
return true;
}
@Override
public boolean contains(@Nullable Object target) {
return false;
}
@Override
public boolean containsAll(Collection<?> targets) {
return targets.isEmpty();
}
@Override
public UnmodifiableIterator<Object> iterator() {
return Iterators.emptyIterator();
}
@Override
boolean isPartialView() {
return false;
}
@Override
int copyIntoArray(Object[] dst, int offset) {
return offset;
}
@Override
public ImmutableList<Object> asList() {
return ImmutableList.of();
}
@Override
public boolean equals(@Nullable Object object) {
if (object instanceof Set) {
Set<?> that = (Set<?>) object;
return that.isEmpty();
}
return false;
}
@Override
public final int hashCode() {
return 0;
}
@Override
boolean isHashCodeFast() {
return true;
}
@Override
public String toString() {
return "[]";
}
Object readResolve() {
return INSTANCE; // preserve singleton property
}
private static final long serialVersionUID = 0;
}